Unfortunately that really seems like a tumor to me. My dog's was probably a different type as it was slow growing and got lumpy when it was bigger and that's smooth. There is some red right around the tooth but the rest isn't. Gum infection would have a lot more of the gums being inflamed. Root of the tooth infection can cause large swelling but usually up higher like under the eye, but I've only dealt with that in dogs. So maybe would swell lower in a raccoon. An infection like that should also be painful but then "wild" animals are good at hiding pain. If you could somehow get a vet to look and aspirate it for a sample you could find out for sure if it's a treatable infection or something worse.

Edit: another sign is that the tooth seems pushed more out than on the other side for that the happen the "swelling" would have to involve the bone, so possible bone cancer.

I would try to find some way for a vet to check though. Can't really diagnose from a photo. Only for sure it taking a bit to look at under the microscope by people who know what they are looking at. But it does look bad :(

I called MANY vets. Even where raccoons are "legal". Found out that NO vet in my state, nor the nearest state will treat him. They all gave me the same answer. It is not legal to have native wildlife and they will not treat them. Believe me, I have exhausted that possibility. In this state there is not even a permit you can get to keep any native wildlife.

A natural thing that might help at least slow it down some would be curcumin, not to be confused with cumin, it's an extract of turmeric. I buy it on amazon from bulk supplements, it keeps my fibroids in check so no pain and bleeding from them since it shrinks them down a bit and gave it to Hyzzie for her liver and kidneys. I gave Hyzzie 1/8-1/4 tsp of the pure powder twice a day. If you really can't find any vet willing to help then at least it would be something to try.

I get this one since it works out the least expensive. It doesn't have much flavor so should be easy to mix in food. Hyzzie would take nothing that way though so I just made a paste of it mixed with some DHA(fish oil) and wiped it in her mouthhttps://www.amazon.com/gp/product/B00GHY368G

Debek60, I PM'd you here, and haven't heard back from you, so I'll post it here. If you're in or near PA, I can recommend someone who would probably see your baby, but I won't post it here publicly. PM me if you want that info.